LBI-31985A
Printed in U.S.A
DESCRIPTION AND MAINTENANCE
851-870 MHz, 100 WATT MASTR II
STATION TRANSMITTER
19D901841G2
DESCRIPTION
The 851-870 MHz, 100 Watt MASTR II transmitter is a
crystal controlled, phase modulated transmitter designed for
single frequency operation. The transmitter utilizes both in-
tegrated circuit (ICs) and discrete components and consists
of the following modules:
•
Exciter Board; with audio, modulator, amplifier and
multiplier stages.
•
Power Amplifier; with or without Antenna Relay.
Figure 1 is a Block Diagram of the 851-870 MHz
MASTR II transmitter, showing the exciter, and the Power
Amplifier assemblies.
The Exciter contains the
±
1 PPM Integrated Circuit Os-
cillator Module (ICOM), audio processor, modulator and
multipliers to provide the station operating frequency.
The PA assembly uses 3 RF amplifier stages to drive a
two transistor power output circuit. Each stage employs
matching networks consisting of discrete components and
strip line technology. The RF output power is fed to the an-
tenna through a circulator containing a low pass filter.
The PA assembly includes a power control module. The
power control module permits adjusting the power output
over a range of 10 to 100 watts. R11 located on the power
control board sets the output level. Three additional adjust-
ments are located on the control board: R2, RS, and R8.
These adjustments are not used in GE MARC applications.
The power adjust must be set for rated output only.
CAUTION
TABLE OF CONTENTS
Page
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Cover
MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
Dissassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
Alignment Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
Troubleshooting Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
ILLUSTRATIONS
Figure 1 - Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
Figure 2 - Correction Factor Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
